#include <fstream>

using namespace std;

int main()
{
    ifstream f("fact.in");
    ofstream g("fact.out");
     long i,s,j,p;
    f>>p;
    if (p==0)
        g<<1;
    else
    if (p<5)
    g<<5*p;
    else
    for (i=p*4;i<=p*5;i=i+5)
    {
        s=0;
        for (j=5;j<=i;j=j*5)
        s+=i/j;
            if(s>p)
            g<<-1;
            else
            if (s==p)
            g<<i/5*5;
    }
    return 0;
}